PCDE Practice Question: Manage a solution that can span multiple database technologies
A gaming company uses Cloud Spanner to store player profiles and game state. They need to run a one-time analytic query on historical data that would take minutes and cannot impact production performance. What is the best approach?
⚠ Common exam trap
The PCDOE exam often tests the misconception that read-only replicas or transactions are fully isolated from production performance, but in Cloud Spanner they still share instance resources and can cause degradation under sustained analytic queries.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Export the required data to BigQuery using Dataflow and run the query there
Exporting the data to BigQuery via Dataflow isolates the analytic workload from Cloud Spanner, ensuring zero impact on production performance. Cloud Spanner is designed for transactional workloads, not heavy analytic queries that take minutes, and BigQuery is purpose-built for such analytics. This approach also avoids consuming Spanner's CPU or memory resources, which could degrade real-time game state operations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a read-only replica and query it
Why it's wrong here
Spanner does not have read-only replicas; all nodes serve reads and writes.
- ✗
Use the gcloud spanner databases execute-sql command with --query-mode=read-only
Why it's wrong here
Even read-only queries consume CPU and can affect performance if heavy.
- ✓
Export the required data to BigQuery using Dataflow and run the query there
Why this is correct
Moving data to BigQuery separates analytic workloads from production.
- ✗
Run the query using a read-only transaction with strong reads
Why it's wrong here
Strong reads still consume resources on the same nodes and can impact production.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDE exam.